The present invention relates to devices for switching light beams between predefined channels and more particularly to a light actuated switching device.
Communication and computational systems utilizing switched light beams have the potential of providing substantial improvements in telephone and computer systems. Fiber optic transmission lines are already being utilized to increase the capacity of telephone systems. Computing devices based on switching light beams hold the promise of dramatic increases in the capacity and speed of computers.
Unfortunately, the maximum speed with which current light switching equipment operates is still limited by the speed with which electrical signals can be turned on and off. For example, optical fiber communication systems still utilize electrical components to switch the laser beams on and off to generate the light pulses at the transmission end of an optical fiber. In addition, such systems utilize light detectors and electrical circuit elements at the receiving end of the fiber to decode the information transmitted on the fiber.
Optical fibers are capable of carrying hundreds of billions of light pulses per second. However, economical electrical circuitry which is capable of differentiating such closely spaced light pulses is not known to the art. As a result, fiber optic communication systems typically operate at a few hundreds of MHz.
In principle, successive light pulses in the optical fiber could be routed to different detectors to reduce the load on any individual detector. Devices for routing a light beam between one of two paths are well known to the optical arts. Such devices utilize an electric field to alter the index of refraction of a medium through which the light beam passes. In its simplest form, such a device has two indices of refraction, corresponding to two electric field states. In one of the states, the light exits the medium through a first port. Light is switched to a second port by applying the appropriate electric field to the medium. The electric field alters the index of refraction of the medium which results in the light being reflected from an interface between two regions having different indices of refraction.
To switch the light between the ports, a voltage must be switched between electrodes on the surface of the medium in question. Hence, the light beam can not be switched faster than the voltage in question is switched. Therefore, such devices have been limited by the speed at which electrical components can switch voltages.
Broadly, it is an object of the present invention to provide an improved light switching device.
It is a further object of the present invention to provide a light switching device which is not limited by the speed at which electrical signals can be switched.
These and other objects of the present invention will become apparent to those skilled in the art from the following detailed description of the invention and the accompanying drawings.